Re: [PATCH] of: skip disabled CPU nodes
From: Frank Rowand <hidden>
Date: 2020-08-26 13:02:20
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On 2020-08-26 07:02, Matthias Schiffer wrote:
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Allow disabling CPU nodes using status = "disabled". This allows a bootloader to change the number of available CPUs (for example when a common DTS is used for SoC variants with different numbers of cores) without deleting the nodes altogether (which may require additional fixups where the CPU nodes are referenced, e.g. a cooling map). Signed-off-by: Matthias Schiffer <redacted> --- drivers/of/base.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/drivers/of/base.c b/drivers/of/base.c index ea44fea99813..d547e9deced1 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c@@ -796,6 +796,8 @@ struct device_node *of_get_next_cpu_node(struct device_node *prev) of_node_put(node); } for (; next; next = next->sibling) { + if (!__of_device_is_available(next)) + continue; if (!(of_node_name_eq(next, "cpu") || __of_node_is_type(next, "cpu"))) continue;
The original implementation of of_get_next_cpu_node() had that check, but status disabled for cpu nodes has different semantics than other nodes, and the check broke some systems. The check was removed by c961cb3be906 "of: Fix cpu node iterator to not ignore disabled cpu nodes". It would be useful to document that difference in the header comment of of_get_next_cpu_node(). -Frank